The present invention relates to a method of coating at least one liquid medium onto a moving material web, in particular of paper or cardboard, in which method the material web is led along a first treatment path in a first mode of operation or along a second treatment path in a second mode of operation, the material web being led
a) along the first treatment path through a roll gap formed by a primary roll and a secondary roll to indirectly apply the liquid medium via the shell surface of the primary roller, or PA1 b) along the second treatment path over a region of the shell surface of the primary roller remote from the roll gap to directly apply the liquid medium on the material web in the mentioned region of the shell surface of the primary roller. PA1 the primary roll is driven in the one rotational direction in the first mode of operation and in the other rotational direction in the second mode of operation, and PA1 the general run-in or run-out direction of the material webs in the region of the primary and secondary rolls is essentially the same along both treatment paths. PA1 a drive with a rotational direction reversal is provided for the primary roll, and PA1 the web guide rolls are arranged in such a manner in the run-in and run-out region of the primary and secondary rolls that they guide the material webs along both treatment paths.
The invention also relates to an apparatus for carrying out this method.
Processing methods and apparatus of the type described above are already generally known. Thus, for example, DE-OS 40 14 647 discloses a processing method and apparatus which are designed in such a manner that the general run-in and run-out direction of the first treatment path is approximately at right angles in the region of the primary and secondary rolls to the general run-in and run-out direction of the second treatment path. In such a concept, the coating mechanisms and devices required for coating the liquid medium can be arranged optimally and in an easily accessible manner in the area of the primary and secondary rolls which are equipped with simple drives. However, this concept must be paid for dearly with a relatively large number of web guide rolls arranged upstream and downstream of the primary and secondary rolls and a not insignificant additional input of technical resources for the web feed.